With rapid development of communications technologies, in a 2×2 MIMO (Multiple-Input Multiple-Output) technology introduced into the version Re1-7 formulated by the 3GPP (3rd Generation Partnership Project), a transport block length indication and a modulation indication of each data flow are independent, a NodeB (base station) informs a UE (User Equipment) of only a process number HAPpb of a primary transport block no matter single-current data or double-current data is scheduled, and a process number of a secondary transport block may be calculated according to the process number of the primary transport block:HAPsb=(HAPpb+Nproc/2)mod(Nproc).
In Re1-7 MIMO, the total number of processes satisfies 6≦Nproc/2≦8, that is, the number of processes of each flow is 6-8 on average.
When 4-antenna MIMO is used, basic data transmission is roughly shown in FIG. 1. After the 3GPP standard conference decides to introduce 4×4MIMO, still at most 2 transport block length indications and 2 modulation indications are used. Each piece of indication information can control at most 2 TBs (Transport Block). Data obtained by coding 1 or 2 TBs using a same set of control information is collectively called a codeword (CW for short). The code is borne at each transport layer after undergoing layer mapping. Data of each transport layer is transferred to multiple antenna ports after being pre-coded, and is sent at an air interface to a receiver after being superimposed with other data signals. Upon receiving air interface data information and corresponding control information, the receiver performs operations such as demodulation decoding, and feeds ACK back/NACK for each codeword to a transmitter according to whether data passes CRC (Cyclic Redundancy Check) verification. If the transmitter receives a NACK feedback, a corresponding codeword needs to be retransmitted.
Currently, in the foregoing process of MIMO-based data retransmission processing, the number of layers or the number of TBs corresponding to each retransmitted codeword does not change, and the sequence of retransmitted codewords remains unchanged; if at the moment, no new data needs to be transmitted, a case that the number of layers that shall be used is greater than the number of layers required for retransmitting the codeword may occur, and in this case, behaviors of the transmitter are not defined yet, so that the transmitter does not know how to perform processing, which may possibly cause it difficult for the transmitter and the receiver to work normally.